HIGH STRENGTH SHIP-BUILDING STEEL WITH EXCELLENT GENERAL CORROSION AND PITTING CORROSION RESISTANCE AT LOW PH CHLORIDE SOLUTION AND MANUFACTURING METHOD FOR THE SAME

摘要

PURPOSE: A high strength ship-building steel material and a manufacturing method thereof are provided to improve the yield strength by controlling the ratio between the maximum length and the maximum width of an inclusion within 30. CONSTITUTION: A high strength ship-building steel material is comprised of: one or more elements selected from the group consisting of C 0.02~0.2 weight%, Si 0.05~1.5 weight%, Mn 0.2~2.0 weight%, P 0.03 weight%, S 0.03 weight%, Cu 0.05~1.0 weight%, Al 0.001~0.1 weight%, N 0.001~0.01 weight%, Ni 0.05~3.0 weight%, Cr 0.02~1.0 weight%, Mo 0.02~0.5 weight%, W 0.02~0.5 weight%, and Ca 0.0005~0.01; one or more elements selected from the group consisting of Nb 0.005~0.1 weight%, V 0.005~0.2 weight%, and Ti 0.005~0.1 weight%; and the rest Fe and an inevitable impurity.